Fuel, Available online 21 September 2013, In Press, Uncorrected Proof
Study of Brazilian asphaltene aggregation by
Nuclear Magnetic Resonance spectroscopy
Emanuele Catarina da Silva Oliveira (a),
Álvaro Cunha Neto (a), Valdemar Lacerda Júnior (a), Eustáquio Vinícius Ribeiro
de Castro (a), Sônia Maria Cabral de Menezes (b)
a Departamento de Química, Centro de Ciências Exatas, Universidade Federal do
Espírito Santo, UFES, Avenida Fernando Ferrari 514, Goiabeiras, 29075-910-Vitória,
ES, Brazil
b Petrobras/Cenpes/QM, Ilha do Fundão, 21941-598 Rio de Janeiro, RJ, Brazil
Abstract
Using Nuclear Magnetic Resonance, researchers
explored the relationship between the structural type (continental or
archipelago) and aggregation properties of three distinct asphaltenes: asph_A,
asph_B and asph_C. They used diffusion-ordered NMR spectroscopy (DOSY) to study
the diffusion coefficients.
They examined the self-diffusion of the
asphaltene aggregates in the concentration range of 0.01–10% of each asphaltene in deuterated toluene.
Data obtained from 1H and 13C NMR suggest that asph_B has
a continental type of structure. This contributes to various properties of
aggregation. DOSY reveals the presence of three aggregates, with three
different diffusion coefficients, called nanoaggregate, microaggregate and
macroaggregate.
Full Text Source (Subscription or Fee): http://www.sciencedirect.com/science/article/pii/S001623611300851X
Showing posts with label SPECTROSCOPY. Show all posts
Showing posts with label SPECTROSCOPY. Show all posts
Thursday, October 24, 2013
Dispersing of Petroleum Asphaltenes by Acidic Ionic Liquid and Determination by UV-Visible Spectroscopy
Journal
of Petroleum EngineeringVolume 2013 (2013), Article ID 203036, 5 pages,
http://dx.doi.org/10.1155/2013/203036
Dispersing of Petroleum Asphaltenes by Acidic Ionic Liquid and Determination by UV-Visible Spectroscopy
Eshagh Rezaee Nezhad, (1), (2) Fariba Heidarizadeh, (1) Sami Sajjadifar, (2) and Zahra Abbasi (2)
1 Department of Chemistry, Faculty of Sciences, Shahid Chamran University, Ahvaz 61357-43337, Iran
2 Department of Chemistry, Payame Noor University, P.O. BOX 19395-4697, Tehran, Iran
Abstract
Constructing a mechanism to prevent the aggregation petroleum asphaltenes by the use of new acidic ionic liquids has become of fundamental importance. In this research, 3-(2-carboxybenzoyl)-1-methyl-1H-imidazol-3-ium chloride ([CbMIM] [Cl]) and other ionic liquids such as [CbMIM]BF4, [HMIM]Cl, [BMIM]Br, and [HMIM]HSO4 were tested. It should be noted that during the experiment the presence of the acidic ionic liquid moiety enhanced interactions between asphaltenes and acidic ionic liquids and it greatly limited asphaltene aggregation. Authors considered parameters such as temperature, amount of dispersant, effect of water: toluene ratio, the stirring time and effects of other ionic liquids, and determination of concentration of petroleum asphaltenes after dispersing by acidic ionic liquid under various parameters using UV-Visible spectroscopy.
Introduction
Asphaltenes precipitation is one of the problems affecting crude oil production and refining processes. asphaltenes change a very high temperature and pressure where asphaltenes are expected to exist in a molecular form.
In this paper, we synthesized the acidic ionic liquid and used a great deal of petroleum asphaltenes’ dispersant. In present study, we observed that the acidic ionic liquid, with the help of its hydrogen bond and electrostatic interaction, prevents asphaltene deposition.
Free Full Text Source: http://www.hindawi.com/journals/jpe/2013/203036/
Dispersing of Petroleum Asphaltenes by Acidic Ionic Liquid and Determination by UV-Visible Spectroscopy
Eshagh Rezaee Nezhad, (1), (2) Fariba Heidarizadeh, (1) Sami Sajjadifar, (2) and Zahra Abbasi (2)
1 Department of Chemistry, Faculty of Sciences, Shahid Chamran University, Ahvaz 61357-43337, Iran
2 Department of Chemistry, Payame Noor University, P.O. BOX 19395-4697, Tehran, Iran
Abstract
Constructing a mechanism to prevent the aggregation petroleum asphaltenes by the use of new acidic ionic liquids has become of fundamental importance. In this research, 3-(2-carboxybenzoyl)-1-methyl-1H-imidazol-3-ium chloride ([CbMIM] [Cl]) and other ionic liquids such as [CbMIM]BF4, [HMIM]Cl, [BMIM]Br, and [HMIM]HSO4 were tested. It should be noted that during the experiment the presence of the acidic ionic liquid moiety enhanced interactions between asphaltenes and acidic ionic liquids and it greatly limited asphaltene aggregation. Authors considered parameters such as temperature, amount of dispersant, effect of water: toluene ratio, the stirring time and effects of other ionic liquids, and determination of concentration of petroleum asphaltenes after dispersing by acidic ionic liquid under various parameters using UV-Visible spectroscopy.
Introduction
Asphaltenes precipitation is one of the problems affecting crude oil production and refining processes. asphaltenes change a very high temperature and pressure where asphaltenes are expected to exist in a molecular form.
In this paper, we synthesized the acidic ionic liquid and used a great deal of petroleum asphaltenes’ dispersant. In present study, we observed that the acidic ionic liquid, with the help of its hydrogen bond and electrostatic interaction, prevents asphaltene deposition.
Free Full Text Source: http://www.hindawi.com/journals/jpe/2013/203036/
Tuesday, November 13, 2012
Cavity-enhanced optical methods for online microfluidic analysis
CATEGORY: SPECTROSCOPY
Chemical Physics Letters, Available online 16 October 2012, In Press, Corrected Proof
Cavity-enhanced optical methods for online microfluidic analysis
Cathy M. Rushwortha,
Joanna Davies b, João T. Cabral b, Philip R. Dolan c, Jason M. Smith c, Claire Vallance a
a Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
b Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
c Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
Abstract
Absorption spectroscopy is a promising detection technique for microfluidic applications, since it is universal, label-free, and rapid. However, the short optical pathlength through a microfluidic channel often imposes unacceptable limits on detection sensitivity.
Authors review a variety of strategies for increasing the pathlength and thereby improving the detection sensitivity of absorption measurements, covering extended-pathlength single-pass methods, multi-pass measurements, and finally a range of cavity-enhanced methods. They conclude that cavity-enhanced approaches show considerable promise for applications in which a high detection sensitivity is required within a small probed volume.
Full Text Source (Subscription or Fee): http://www.sciencedirect.com/science/article/pii/S000926141201158X
Chemical Physics Letters, Available online 16 October 2012, In Press, Corrected Proof
Cavity-enhanced optical methods for online microfluidic analysis
Cathy M. Rushwortha,
Joanna Davies b, João T. Cabral b, Philip R. Dolan c, Jason M. Smith c, Claire Vallance a
a Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
b Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
c Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
Abstract
Absorption spectroscopy is a promising detection technique for microfluidic applications, since it is universal, label-free, and rapid. However, the short optical pathlength through a microfluidic channel often imposes unacceptable limits on detection sensitivity.
Authors review a variety of strategies for increasing the pathlength and thereby improving the detection sensitivity of absorption measurements, covering extended-pathlength single-pass methods, multi-pass measurements, and finally a range of cavity-enhanced methods. They conclude that cavity-enhanced approaches show considerable promise for applications in which a high detection sensitivity is required within a small probed volume.
Full Text Source (Subscription or Fee): http://www.sciencedirect.com/science/article/pii/S000926141201158X
Subscribe to:
Posts (Atom)